KR20120032267A - Scalable centralized network architecture with de-centralization of network control and network switching apparatus therefor - Google Patents

Abstract

PURPOSE: A central studio network structure, control method, and network switching apparatus are provided to expand roles of a switching apparatus by distributing roles of a network control unit in a central studio network structure. CONSTITUTION: A flow classification unit classifies input packets according to each flow(315). A table management unit searches a flow group table in case the flow corresponding to the packet is not existed in the flow table(325, 330). In case the flow included in the flow group is existed in the flow group table, a packet processing unit applies the packet at an action corresponding to the flow group(335, 355).

Description

Scalable centralized network architecture with de-centralization of network control and network switching apparatus therefor}

The present invention relates to a network structure, and more particularly, to a centralized network structure and control method and a network switching device therefor.

As a path determining method of a packet used in an existing network, a routing method based on "agreeed protocol and algorithm" operating in each switching device is mainly used. Here, each switching device exchanges information according to the agreement agreed upon with each other, and determines the path between the transmitting host and the receiving host based on the mutual connection information collected therefrom.

This distributed network path determination method automatically determines and modifies the path based on the information on the network topology collected by the agreed protocol, so that each protocol can provide the protocol according to the agreed protocol. Provides stability and scalability. However, with the diversified contents and applications that users exchange through the Internet, the quality of service (QoS) requirements of users have been diversified, and in the autonomous network path determination method based on the previously promised protocols, user needs There is no limit to satisfying the matter. Accordingly, various modification algorithms have been proposed to satisfy user requirements, but there are limitations to satisfy various user requirements, and there are practical limitations in implementing them to be used in the entire Internet environment. For example, in the case of IP multicast, not only technical details but many routing devices are sold with this function. However, due to the limitations of billing, traffic control, and difficulty in configuration and management, Internet service providers generally use IP. It does not utilize the multicast function.

In various aspects, there is a continuous demand for the development of a technology that can satisfy the more complex user requirements at the same time as the use of the Internet, and how to overcome the limitations of practical use. One of the technologies attracting attention as a way to solve this demand is a method in which a centralized network path control entity manages control of a network and a network path control entity instructs each switching device to dynamically connect a path. Each switching device is connected to a network controller through a network and is controlled by the network controller. A network control unit and a plurality of switching devices form a network control domain, and the network control unit independently determines a path connection and instructs each switching device without a complicated routing protocol.

According to such a centralized network control structure, a network controller having all information on network connection directly determines a network path for each flow and instructs the switching equipment. Since the network controller has a connection with all the switching equipment, it is possible to check the result of processing the flow in the switching equipment according to the control result as well as the network topology. Therefore, the network control is simplified, so that the QoS required by the user for each flow can be easily satisfied. Due to these advantages, centralized network control structures are being studied in many future Internet-related studies, and researches are being conducted to manage large amounts of data and apply them to environments such as data center networks where efficiency is important.

However, according to the centralized network control structure, there is a lot of traffic on the Internet, and the number of flows that can be processed is limited according to the capability of the control agent because the centralized control agent must control the flow directly for all flows. There is. In other words, scalability is a problem depending on the performance and throughput of the control principal.

The technical problem to be achieved by the present invention is a centralized network structure and method that can provide scalability of the network control by distributing a part of the role of the network controller, which is the controlling agent in the centralized network control structure, to individual switching devices, and the central The present invention provides a network switching device for a centralized network structure.

In order to solve the above technical problem, the centralized network control method according to the present invention includes: classifying a packet input from a network for each flow based on header information of the packet; Determining whether a flow corresponding to the packet exists in a flow table in which action information to be taken for each flow is stored; If a flow corresponding to the packet does not exist in the flow table, it is determined whether a flow set to which the flow corresponding to the packet belongs exists in a flow set table in which action information about flow sets representing a plurality of flows related to each other is stored. Making; And when a flow set to which the flow corresponding to the packet belongs exists in the flow set table, applying the action corresponding to the flow set to the packet.

The control method may further include applying an action corresponding to the flow to the packet when a flow corresponding to the packet exists in the flow table.

The control method may further include transmitting the packet to a network controller when there is no flow set to which the flow corresponding to the packet belongs in the flow set table.

The control method may include updating the flow table by adding the flow corresponding to the packet and the received action information to the flow table when the action information on the flow corresponding to the packet is received from the network controller. It may further include.

When the control method receives the action information on the flow set corresponding to the packet from the network controller, the flow set table is updated by adding the flow set corresponding to the packet and the received action information to the flow set table. It may further comprise the step.

In order to solve the above technical problem, a network switching device for a centralized network structure according to the present invention includes: a flow classification unit for classifying a packet input from a network for each flow based on header information of the packet; A table storage unit configured to store a flow table in which action information to be taken for each flow is stored and a flow set table in which action information on flow sets representing a plurality of flows related to each other is stored; It is determined whether a flow corresponding to the packet exists in the flow table. When the flow corresponding to the packet does not exist in the flow table, it is determined whether a flow set to which the flow corresponding to the packet belongs exists in the flow set table. A table manager; And a packet processing unit for applying an action corresponding to the flow set to the packet when the flow set to which the flow corresponding to the packet belongs exists in the flow set table.

The packet processor may apply an action corresponding to the flow to the packet when a flow corresponding to the packet exists in the flow table.

The packet processor may transmit the packet to the network controller when the flow set to which the flow corresponding to the packet belongs does not exist in the flow set table.

When the table manager receives the action information on the flow corresponding to the packet from the network controller, the table manager may update the flow table by adding the flow corresponding to the packet and the received action information to the flow table.

When the table manager receives the action information on the flow set corresponding to the packet from the network controller, the table manager may update the flow set table by adding the flow set corresponding to the packet and the received action information to the flow set table. Can be.

In order to solve the above technical problem, the centralized network structure according to the present invention stores a flow table storing action information to be taken for each flow and a flow set table storing action information for a flow set representing a plurality of flows related to each other, When a packet input from a network is classified for each flow based on the header information of the packet, it is determined whether a flow corresponding to the packet exists in the flow table, and if a flow corresponding to the packet does not exist in the flow table. It is determined whether a flow set to which a flow corresponding to the packet belongs exists in the flow set table, and if a flow set to which a flow corresponding to the packet belongs exists in the flow set table, the packet corresponds to the flow set. liquid If the application, and the flow table, the flow set belonging to the set flow for the packet does not exist a network switching device to the packet sent to the network controller; And a network controller configured to determine action information on a flow corresponding to the packet or action information on a flow set corresponding to the packet when the packet is received, and transmit the determined action information to the network switching device.

When there is a flow corresponding to the packet in the flow table, the network switching device may apply an action corresponding to the flow to the packet.

When the network switching device receives the action information on the flow corresponding to the packet from the network controller, the network switching device may update the flow table by adding the flow corresponding to the packet and the received action information to the flow table. have.

When the network switching device receives the action information on the flow set corresponding to the packet from the network controller, the network switching device adds the flow set corresponding to the packet and the received action information to the flow set table. You can update it.

The network controller may determine an action for a specific flow or flow set, and update the flow table or the flow set table stored in the network switching device according to the determination.

According to the present invention described above, in the centralized network control structure, the role of the network controller can be distributed to the switching device to expand the role of the switching device, and at the same time, to provide the scalability of the network control by reducing the burden of the network controller, which is the control agent. Can be.

1 illustrates a centralized network structure according to an embodiment of the present invention.
2 shows a block diagram of a network switching device 20 according to an embodiment of the present invention.
3 is a flowchart illustrating a centralized network control method according to an embodiment of the present invention.
4 is an example of a flow table.
5 is an example of a routing table used in a general IP network.
6 is an example of defining a flow aggregation table with the routing table of FIG. 5.
FIG. 7 is an example of a flow aggregation table defined based on FIG. 4.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and the accompanying drawings, substantially the same components are denoted by the same reference numerals, and redundant description will be omitted. In addition, in the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 illustrates a centralized network structure according to an embodiment of the present invention.

Each network switching device 20 is connected to the network control unit 10 via a network and is controlled by the network control unit 10. The network control unit 10 and the plurality of network switching devices 20 form a network control domain, and the network control unit 10 independently determines a path connection and instructs each switching device without a complicated routing protocol. That is, each network switching device 20 processes the packet according to the instruction of the network controller 10 when a packet is input from the network.

However, when the flow corresponding to the packet is registered in the flow table or registered in the flow set table, the action corresponding to the flow or the flow set in the flow table or the flow set table is not received by the network controller 10. Process packets according to the information.

That is, the network switching device 20 classifies a packet input from the network for each flow based on the header information of the packet, manages a flow table storing action information to be taken for each flow, and corresponds to a flow registered in the flow table. For packets, the network controller 10 directly processes the switching device 20 without receiving an instruction, thereby providing efficiency of transmission. In addition, the network switching device 20 manages a flow set table in which action information on flow sets representing a plurality of flows related to each other is stored, and belongs to a flow set not registered in the flow table but registered in the flow set table. The network controller 10 directly processes the packets corresponding to the flow without being instructed by the network controller 10.

2 shows a block diagram of a network switching device 20 according to an embodiment of the present invention. Referring to FIG. 2, the network switching device 20 according to an embodiment includes a flow classification unit 21, a table storage unit 22, a table management unit 23, and a packet processing unit 24. Although not shown, the network switching device 20 may include a plurality of ports, and each port may have a media access control (MAC).

The flow classifying unit 21 classifies a packet input from the network for each flow based on the header information of the packet. The flow classifying unit 21 may be implemented as a processor for data comparison and calculation in a typical computing environment and a memory capable of loading and processing data necessary for a task.

The table storage unit 22 stores a flow table in which action information to be taken for each flow is stored and a flow set table in which action information for a flow set representing a plurality of flows related to each other is stored.

The table storage unit 22 is a data storage capable of reading and writing data, and the data storage may include random access memory (RAM), flash memory, hard disk, floppy disk, compact disk, video disk, or optical recording medium. It includes.

The table manager 23 determines whether a flow corresponding to the packet exists in the flow table, and when the flow corresponding to the packet does not exist in the flow table, the flow set to which the flow corresponding to the packet belongs in the flow set table. Determine if it exists.

The table manager 23 may also be implemented as a processor for comparing and computing data in a typical computing environment, and a memory capable of loading and processing data necessary for a task.

If the flow corresponding to the packet exists in the flow table according to the determination result of the table manager 23, the packet processing unit 24 applies the corresponding action, and the flow set to which the flow corresponding to the packet belongs is included in the flow set table. If present, the action is applied. If a flow and a flow set corresponding to the packet do not exist in the flow table and the flow set table, action information is requested by transmitting the packet to the network controller 10.

The packet processor 24 may also be implemented as a processor for data comparison and operation in a typical computing environment and a memory capable of loading and processing data necessary for a task.

3 is a flowchart illustrating a centralized network control method according to an embodiment of the present invention. The network switching device 20 shown in FIG. 2 is described in more detail with reference to FIG. 3 below.

In step 310, a packet is input from the network to the network switching device 20.

Then, the flow classifying unit 21 classifies the packet for each flow based on the header information of the packet (step 315).

Here, the flow refers to a unit of end-to-end traffic specified by using an attribute contained in the header information of the packet for the packets constituting the traffic. Here, the attribute may be, for example, an input port, a sending host Ethernet address, a receiving host Ethernet address, an Ethernet type, a VLAN ID, a VLAN priority, a sending host IP address, a receiving host IP address, a sending host port number, a receiving host port number, and the like. have. Of course, the flow classification method can be variously extended using additional packet header information.

The table storage unit 22 stores a flow table in which action information to be taken for each flow is stored. 4 is an example of a flow table. The flow table manages a port number for outputting a packet as action information to be taken for each flow. For example, the header information of the packet is in_port = 0, dl_src = 00: 00: 00: 00: 00: 11, dl_dst = 00: 00: 00: 00: 00: 22, nw_src = 1.1.1.1, nw_dst = 2.2.2.2 The action information for the flow with nw_proto = 7, tp_src = 20, and tp_dst = 80 is “output: 1”, which means to output the packet to port 1.

Here, the action information may be "DROP" or "FORWARD" of the packet, and "forwarding" may be "output to a specific port" among the ports of the network switching device 20, or "Output to all ports except the port where the packet came in", and so on. Alternatively, the network switching device 20 maintains / manages a plurality of forwarding tables according to a protocol agreed with other network switching devices, and refers to a specific forwarding table as action information for packets corresponding to a given flow or set of flows. To determine the path. In this case, the network switching devices operate in the same way as the existing distributed network path determining method by exchanging information according to an agreed protocol.

When the packet is classified by flow, the table manager 23 searches the flow table to determine whether a flow corresponding to the packet exists in the flow table (step 320).

If there is a flow corresponding to the packet in the flow table in step 325, the flow proceeds to step 355, and the packet processor 24 applies an action corresponding to the flow in the flow table to the packet. For example, if a packet is in_port = 0, dl_src = 00: 00: 00: 00: 00: 11, dl_dst = 00: 00: 00: 00: 00: 22, nw_src = 1.1.1.1, nw_dst = 2.2.2.2, nw_proto = 7, if tp_src = 20 and tp_dst = 80, the packet is output to port 1.

If the flow corresponding to the packet does not exist in the flow table in step 325, the flow proceeds to step 330 and the table manager 23 determines the flow set to determine whether a flow set to which the flow corresponding to the packet belongs exists in the flow set table. Search for a table.

If there is a flow set to which the flow corresponding to the packet exists in the flow set table in step 335, the flow proceeds to step 355, and the packet processor 24 applies an action corresponding to the flow set in the flow set table to the packet.

Referring to FIG. 2, the table storage unit 22 stores a flow set table in which action information on flow sets representing a plurality of flows related to each other is stored. When a flow that is not registered in the flow table is received, the network controller 10 may request a network controller 10 to receive an instruction and process it, thereby limiting scalability. Therefore, in an embodiment of the present invention, in view of the fact that it is possible to apply the same action to flows that are related to each other, a plurality of flows that are related to each other are collectively represented as a flow set and flows belonging to the flow set. For x, extensibility is provided by applying the same action.

Here, as an example of 'relevance', there is a case in which a certain part of the header information of the packet matches. For example, flows in which the destination address is a specific IP address may be configured in a single flow set, and flows destined for a specific subnet may be configured in a single flow set.

Alternatively, as another example of a 'relevant case', the context of a flow may be grasped to configure flows related to the context as a single flow set. For example, a user's request using a P2P service may be identified and flows having a request similar to the request may be configured as a single flow set.

As an example of a flow aggregation, a subnet concept used in a general IP network may be utilized. 5 is an example of a routing table used in a general IP network. In FIG. 5, each item (row) represents a specific subnet and has information on which port to forward traffic for the traffic to that subnet. A flow aggregation table is defined with the routing table of FIG. 5, for example, as shown in FIG. 6. The illustrated flow set table means that the destination IP address and the netmask apply the same action to the flow set as registered in the flow set table. For example, it means outputting to port 1 for flows having a destination IP address of 5.0.0.0 and a netmask of 8 (255.0.0.0).

As another example of the flow set, the sender and the receiver may apply the same action by combining the same flows into one flow set. Each entry in the flow table shown in FIG. 4 contains action information for flows from sender address 1.1.1.1 to receiver address 2.2.2.2. FIG. 7 illustrates an example of a flow aggregation table defined based on FIG. 4. The depicted flow set table means output to port 1 for flows with a sender address of 1.1.1.1 and a receiver address of 2.2.2.2. When a flow comes in with a sender address of 1.1.1.1 and a receiver address of 2.2.2.2, it first searches the flow table and processes the flow and action information accordingly if it exists, and if it does not exist in the flow table, It retrieves the result and outputs the packet to port 1.

If a sender address and a receiver address are the same but flows that are not registered in the flow table are received, if the flow table is dependent only on the flow table, the network controller 10 needs to process and receive an instruction. For example, when two end A and B exchange data through port 80, the data is exchanged through port 81, a new flow table entry corresponding thereto is required, and the network switching device 20 transmits the data to the network controller 10. ). However, if the flow set and action information corresponding to the two end points A and B are registered in the flow set table, the network switching device 20 can directly process the network control unit 10 without inquiring.

Reference is again made to FIG. 3. If there is no flow corresponding to the packet in the flow aggregation table in step 335, the process proceeds to step 340 and the packet processing unit 24 requests the network control unit 10 to instruct it by transmitting the packet to the network control unit 10. .

The network controller 10 receiving the packet transmits the action information on the flow corresponding to the received packet or the action information on the specific flow set corresponding to the received packet to the network switching device 20.

The network switching device 20 receives the action information on the flow or the flow set from the network controller 10 (step 345). Then, the table manager 23 of the network switching device 20 updates the flow table or the flow set table by adding the received flow information and the corresponding action information or the received flow set information and the corresponding action information to the flow table or the flow set table. (Step 350). Of course, the network control unit 10 may provide only the action information on the flow to the network switching device 20, may provide only the action information on the flow set to the network switching device 20, both the flow and the flow set Action information on the network switching device 20 may be provided. The network switching device 20 updates the flow table or the flow aggregation table according to the received information.

When the flow table or the flow set table is updated, the packet processing unit 24 applies the action to the packet (step 355).

Meanwhile, the network controller 10 may modify or update the flow table or the flow set table maintained by the network switching device 20 as necessary. The network controller 10 determines and determines an action for a specific flow or a specific flow set when it is determined that packet processing according to the flow table or the flow set table results in poor results or is deemed necessary through periodic monitoring of the network. The flow table or the flow set table of the network switching device 20 can be updated accordingly. If it is determined that an action modification for a specific flow or flow set is necessary, the network switching device 20 transmits a message requesting to modify the flow table or flow set table. Modifications to the flow table or flow set table may be determined by the network administrator or may be determined according to a predefined algorithm.

Meanwhile, the above-described embodiments of the present invention can be written as a program that can be executed in a computer, and can be implemented in a general-purpose digital computer that operates the program using a computer-readable recording medium. The computer-readable recording medium may be a magnetic storage medium (for example, a ROM, a floppy disk, a hard disk, etc.), an optical reading medium (for example, a CD-ROM, DVD, etc.) and a carrier wave (for example, the Internet). Storage medium).

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

Claims (15)

As a centralized network control method,
Classifying a packet input from a network for each flow based on header information of the packet;
Determining whether a flow corresponding to the packet exists in a flow table in which action information to be taken for each flow is stored;
If a flow corresponding to the packet does not exist in the flow table, it is determined whether a flow set to which the flow corresponding to the packet belongs exists in a flow set table in which action information about flow sets representing a plurality of flows related to each other is stored. Making; And
And if the flow set to which the flow corresponding to the packet belongs exists in the flow set table, applying the action corresponding to the flow set to the packet. The method of claim 1,
And if a flow corresponding to the packet exists in the flow table, applying the action corresponding to the flow to the packet. The method of claim 1
And if there is no flow set to which the flow corresponding to the packet belongs in the flow set table, transmitting the packet to a network controller. The method of claim 3,
And when the action information on the flow corresponding to the packet is received from the network controller, updating the flow table by adding the flow corresponding to the packet and the received action information to the flow table. Centralized network control method. The method of claim 3,
If the action information on the flow set corresponding to the packet is received from the network controller, updating the flow set table by adding the flow set corresponding to the packet and the received action information to the flow set table. Centralized network control method, characterized in that. A network switching device for a centralized network structure,
A flow classification unit for classifying a packet input from a network for each flow based on the header information of the packet;
A table storage unit configured to store a flow table in which action information to be taken for each flow is stored and a flow set table in which action information on flow sets representing a plurality of flows related to each other is stored;
It is determined whether a flow corresponding to the packet exists in the flow table. When the flow corresponding to the packet does not exist in the flow table, it is determined whether a flow set to which the flow corresponding to the packet belongs exists in the flow set table. A table manager; And
And a packet processing unit for applying an action corresponding to the flow set to the packet when a flow set to which the flow corresponding to the packet exists exists in the flow set table. The method of claim 6,
And the packet processing unit applies an action corresponding to the flow to the packet when a flow corresponding to the packet exists in the flow table. The method of claim 6
And the packet processing unit transmits the packet to a network controller when there is no flow set to which the flow corresponding to the packet exists in the flow set table. The method of claim 8,
When the table manager receives the action information on the flow corresponding to the packet from the network controller, the table manager updates the flow table by adding the flow corresponding to the packet and the received action information to the flow table. Network switching device. The method of claim 8,
When the table manager receives the action information on the flow set corresponding to the packet from the network controller, the table manager updates the flow set table by adding the flow set corresponding to the packet and the received action information to the flow set table. Network switching device, characterized in that. As a centralized network structure,
Stores a flow table that stores the action information to be taken for each flow and a flow set table that stores the action information for a flow set representing a plurality of related flows, and classifies packets inputted from the network by flow based on the header information of the packet. Determine whether a flow corresponding to the packet exists in the flow table; and if a flow corresponding to the packet does not exist in the flow table, a flow set to which the flow corresponding to the packet belongs exists in the flow set table If there is a flow set to which the flow corresponding to the packet belongs in the flow set table, the action corresponding to the flow set is applied to the packet, and the flow corresponding to the packet is included in the flow set table. Belonging If the low-set does not exist, the network switching device to the packet sent to the network controller; And
When the packet is received, the centralized network comprising a network control unit for determining the action information for the flow corresponding to the packet or the action information for the flow set corresponding to the packet and transmits it to the network switching device. rescue. The method of claim 11,
And the network switching device applies an action corresponding to the flow to the packet when a flow corresponding to the packet exists in the flow table. The method of claim 11,
The network switching device updates the flow table by adding the flow corresponding to the packet and the received action information to the flow table when the action information on the flow corresponding to the packet is received from the network controller. Features a centralized network structure. The method of claim 11,
When the network switching device receives the action information on the flow set corresponding to the packet from the network controller, the network switching device adds the flow set corresponding to the packet and the received action information to the flow set table. Centralized network structure, characterized in that the step of updating. The method of claim 11,
The network controller determines an action for a specific flow or a flow set, and updates the flow table or the flow set table stored in the network switching device according to the determination.

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